JOIN
Section: User Commands (1)
Updated: April 29, 1985
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NAME
join - relational database operator
SYNOPSIS
join
[
options
]
file1 file2
DESCRIPTION
Join
forms, on the standard output,
a join
of the two relations specified by the lines of
file1
and
file2.
If
file1
is `-', the standard input is used.
File1
and
file2
must be sorted in increasing ASCII collating
sequence on the fields
on which they are to be joined,
normally the first in each line.
There is one line in the output
for each pair of lines in
file1
and
file2
that have identical join fields.
The output line normally consists of the common field,
then the rest of the line from
file1,
then the rest of the line from
file2.
Fields are normally separated by blank, tab or newline.
In this case, multiple separators count as one, and
leading separators are discarded.
These options are recognized:
- -an
-
In addition to the normal output,
produce a line for each unpairable line in file
n,
where
n
is 1 or 2.
- -e s
-
Replace empty output fields by string
s.
- -jn m
-
Join on the
mth
field of file
n.
If
n
is missing, use the
mth
field in each file.
- -o list
-
Each output line comprises the fields specified in
list,
each element of which has the form
n.m,
where
n
is a file number and
m
is a field number.
- -tc
-
Use character
c
as a separator (tab character).
Every appearance of
c
in a line is significant.
SEE ALSO
sort(1), comm(1), awk(1)
BUGS
With default field separation,
the collating sequence is that of
sort -b;
with
-t,
the sequence is that of a plain sort.
The conventions of
join, sort, comm, uniq, look
and
awk(1)
are wildly incongruous.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- SEE ALSO
-
- BUGS
-
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